Constrained geometry ligands and complexes derived therefrom

ABSTRACT

A novel constrained geometry titanium(II) diene complex and ligands of such complexes are described. The novel complex has an olefin polymerization activity substantially in excess of a defined activity standard characteristic of analogous prior art constrained geometry diene complexes. Methods for the synthesis of the novel, high-activity complexes are described.

FIELD OF THE INVENTTON

[0001] This invention relates to constrained geometry complexes of group4 metals and dienes characterized by high olefin polymerizationactivity, to ligands of such complexes and to methods for the productionof such complexes and ligands.

BACKGROUND OF THE INVENTION

[0002] U.S. Pat. No. 5,470,993 describes the synthesis of constrained ;geometry group 4 metal diene complexes by contacting a reduced form of agroup 4 metal tetrahalide, a diene and an appropriate dianion ligand ofthe desired metal complex.

[0003] The diene complexes may have the formula which appears at lines20-34 of Column 5 of U.S. Pat. No. 6,015,916 as follows:

[0004] The corresponding dihalo ligand may have the formula also setforth in U.S. Pat. No. 6,015,916 (see Formula II of claim 1):

[0005] The ligand may be any corresponding dihalo compound in which thechlorine substituents are replaced by bromine, iodine or fluorine and inwhich the “t-bu” substituent is replaced by any alkyl group.

[0006] U.S. Pat. No. 6,015/916 describes the synthesis of similarcomplexes by treatment of a dihalo ligand of a metallocene compound withan alkali metal alkyl and a diene. The specification of U.S. Pat. No.6,015,916 is, by express reference, incorporated herein and made a partof this specification.

[0007] German Application DE 197 39 946 A1 describes a metallocenesynthesis in which an appropriate ligand is converted to a metalloceneby treatment with an adduct of Formula (I)

M¹X_(n)D_(a)

[0008] in which M¹ denotes a metal of groups 3, 4, 5 or 6 of theperiodic system of elements (PSB) or an element of the group oflanthanides or actinides, preferably titanium, zirconium, or hafnium, byspecial preference zirconium; X is the same or different, being halogen,a C₁₋₁₀-alkoxy, C₆₋₁₀-aryloxy, C₁₋₁₀-alkylsulfonate such as mesylate,triflate, nonaflate, a C₆₋₁₀arylsulfonate such as tosylate, benzenesulfonate, a C₁₋₁₀-alkylcarboxylate such as acetate, formate, oxalate,or a 1,3-dicarbonylate such as acetylacetonate or a fluorinated1,3-dicarbonylate; n is an integer and equals 2, 3, 4, 5 or 6 andcorresponds to the oxidation number of the metal M¹; a is an integer ora fraction number and 0<a≦4; and D is a linear, cyclic, or branchedoligoether or polyether containing at least two oxygen atoms or anoligoether or polyether containing at least two sulfur atoms.

[0009] There is a need for group 4(II) diene complexes of high catalyticactivity in which these disadvantages are reduced or eliminated and fordihalo ligands of such complexes.

[0010] Accordingly, it is an object of this invention to provide novelcyclopentadienyl group 4 metal diene complexes and dihalo ligands orsuch complexes which provide uniquely active olefin polymerizationcatalysts.

[0011] It is a related object of the invention to providecyclopentadienyl group 4 metal diene complex single site polymerizationcatalysts and catalyst compositions of low impurity content such thatthe single site functionality thereof is not significantly impaired.

[0012] It is a specific object of the invention to provide amagnesium-free cyclopentadienyl group 4 metal diene complex metallocene.

Definitions

[0013] The following expressions have the meaning set forth:

[0014] (1) Cyclopentadienyl group means cyclopentadienyl,tetraalkylcyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl,tetrahydrofluorenyl, or octahydrofluorenyl.

[0015] (2) The expressions group 4(II) and group 4(III) mean a is; group4 metal of valence 2(II) or 3(III).

[0016] (3) A Group 4(II) metallocene compound is a compound comprised ofa group 4(II) metal bonded to one or more cyclopontadienyl groups.

[0017] (4) A Group 4(II) metallocene ligand is a chemical precursorwhich contains a cyclopentadienyl or substituted cyclopentadienyl groupfrom which a group 4(II) metallocene may a synthesized.

[0018] (5) Constrained geometry compound or catalyst (CGC) means acatalyst in which the metal conter is contained in a ring structure andcovalently bonded to a cyclic group via a delocalized n-system andcovalently bonded via a sigma-bond to another atom, e.g., carbon,nitrogen, oxygen. A small ring size induces constraint about the metalatom center. For titanium-containing CGCs, the incorporated titaniumatom can be in the +4, +3, or +2 formal oxidation state. See EPapplication 90309496.9, WO 95/00526 and U.S. Pat. No. 5,470,993.

[0019] (6) CpSA ligand means (t-butylamino)(tetramethylcyclopentadienyl) dimethylsilane.

[0020] (7) (CpSA) means doubly-deprotonated CpSA ligand.

[0021] (8) (CpSA)2-TiCl₂ means [(t-butylamido)(tetramethylcyclopentadienyl) dimethylsilan]titanium dichloride.

[0022] (9) Activity means generally the quantity of polymer producedunder standard conditions by a defined amount of catalyst per unit time.

Catalytic Activity Determination

[0023] As used in this application, catalyst efficiency or activity isbased on ethylene consumption in a batch reactor under standardconditions for temperature, solvent, monomer quantities, hydrogenquantities, monomer pressure and run time.

[0024] The activity of the sample catalyst is reported as the percentageof activity of the sample versus the activity of a standard (“standardactivity”). For purposes of this application, the “standard” is the CGCgroup 4(II) diene complex from Boulder Scientific Company Batch 459-0140of 1997.

[0025] The equation for reporting the sample catalyst activity is asfollows:${\% \quad {Activity}} = {{\frac{{Average}\quad {Sample}\quad {Activity}}{{Average}\quad {Standard}\quad {Activity}} \times 100} = {{Sample}\quad {Activity}}}$

[0026] “Average” means the average of two runs with activities MTS whichare the same within plus or minus 5%.

“Process Description” and “Reaction” for “Standard” CGC BSC-1459-4-0140Dated Feb. 26, 1997

[0027] Process Description

[0028] This process involves making reactant slurries 1 and 2 inseparate vessels and then combining these slurries for the finalreaction. Slurry 1 is produced by charging toluene into a vessel anddeoxygenating. Then titanium tetrachloride is added, followed by addingn-butyllithium. This addition is very exothermic. The resulting mixturecomprising slurry 1 is stirred for 1 hour. This process is illustratedby equation 1);

[0029] Slurry 2 is made up as follows: Toluene and CpSA ligand arecharged to a reaction vessel. After adjusting the pot temperature to45-50° C., a solution of isopropylmagnesium chloride in ethyl ether isfed into the reaction vessel resulting in gas evolution. Gentle heatingis used as needed in order to end up with a pot temperature of 45-50° C.at the end of the Grignard feed. The reaction mixture is slowly heatedand solvents begin to distill along with increased gas evolution. Thereaction mixture is heated up to 85-90° C., and this temperature ismaintained for 2 hours. After allowing the reaction mixture to cool to60-65° C., TiCl₃ is fed into the reaction vessel. The reaction mixtureis then cooled to 20-25° C. This becomes known as Slurry 2. This processis illustrated by equations 2) and 3);

[0030] The agitated Slurry 1 is transferred into the reactor containingthe agitated Slurry 2 as quickly as possible resulting in about atemperature increase of about 7-15° C. Methylene chloride is thencharred to the reaction vessel, the vessel containing Slurry 1 is thenrinsed out with toluene and charged to the Slurry 2 reaction vessel, andthis mixture is then agitated for 2 hours. A dark reddish-brown color isnoted in the reaction vessel as soon as Slurry 1 is introduced. Thisreaction is illustrated by equation 4):

[0031] Solvents are removed under reduced pressure (60-80 mm Hg) using arotary vane vacuum pump to about ½ of the starting volume. Toluene isadded back, Celite is added, and the mixture is filtered through thelarge sparkler filter. Solvents are then distilled to concentrate theproduct. The remaining crude product solution is then used directly inthe next step.

Process Description” and “Reaction” for Conversion of CGC Dichiloide toa (Group 4(II) Diene Complex

[0032] Process Description

[0033] The crude product from the previous steps of this process,equations 1) to 4) which is still contained in the reactor used isagitated at a pot temperature of 20-25° C. and piperylene concentrate (1,3-pentadiene) is added.

[0034] Butylmagnesium chloride in TKF is fed into the reactor. Thereaction is exothermic. When the Grignard feed is done, the reactionmixture is agitated for an additional ½ hour at a pot temperature of35-40° C.

[0035] This mixture is then distillod atmospherically to a pottemperature of 85° C., cooled to 20-25° C., and then vacuum distilled at≦65° C. One drum of deoxgenated hydrocarbon solvent and Celite is addedat 20-25° C., and the resulting mixture is filtered through the large 33inch sparkler. The filter cake is hydrolyzed. The resulting solution isthen vacuum distilled at ≦65° C.

[0036] Six drums of deoxygenated Isopar are charged to the reactor, 2drums at a time, and then vacuum distilled at <65° C. to remove THF andtoluene. When the solvent concentrations are appropriate, 1 drum ofdeoxygenated Isopar and Celite are added. The resulting solution isfiltered through a precoated small sparkler filter into a cylinder. Thefilter cake may be discarded. The reaction is illustrated by thefollowing equation 5).

SUMMARY OF THE INVENTION

[0037] The invention provides ligands of novel constrained geometryGroup 4(II) diene complexes and complexes derived therefrom which havean olefin polymerization activity significantly greater than thatdemonstrated by known complexes of the same type.

[0038] In particular, the invention provides complexes of the formula

[0039] which have an olefin activity substantially in excess of 100%,e.g., at least about 130%, of the aforesaid “standard activity”.

[0040] Pursuant to one aspect of the invention, a cyclopentadienyl silylamine is treated with an alkali metal alkyl and thereafter with adialkyl silyl dihalide to produce cyclopentadienyl silyl amine ligand(CpSA ligand). The ligand is treated with a group 4 metal tetrahalideadduct of a linear ether having at least two oxygen atoms and an alkalimetal alkyl to produce a dihalide ligand of the ultimately desired group4(II) complex having the formula:

[0041] The dihalide ligand is treated with a diene and an alkali metalalkyl used in stoichiometric excess. Dienes useful in the invention aredescribed in U.S. Pat. Nos. 5,470,993 and 6,015,916. The unreactedalkali metal alkyl in the consequent reaction mixture is quenched, forexample, by chlorotrimethyl silane. The complex so produced isapparently free or substantially so of impurities which may result inundesirable gel formation and impair single site olefin polymerizationfunctionality.

DETAILED DESCRIPTION OF THE INVENTION

[0042] Various group 4 metal tatrachoride-ether adducts are known. See,generally, U.S. Pat. No. 5,470,993 and published German application DE197 30 94 A1. Each of top adducts described in these references isuseful in this invention. The 1,2-dimethoxyethane (DME) adducts arepreferred.

[0043] One method for preparing a DME group 4 metal tetrahalide adductis described in U.S. Pat. No. 6,015,916, Col. 4, II. 61-66. Moregenerally useful adducts are prepared by treating from any compound offormula X.OYO.OX in which X is a C₁ to C₁₀ alkyl group, and Y is a C₂ toC₁₀ alkane.

[0044] Any group 4 tetrahalide-ether adduct may be used. Titaniumtetrachloride DME adducts are preferred. The adduct is preferablyprepared in a hydrocarbon solvent. The mol ratio of the reactants ispreferably about 1:1 with a small excess of the ether reactant.

[0045] Any alkali metal alkyl having the formula A—R, in which A may beany alkali metal, preferably lithium, and R is any alkyl group,preferably a C₁ to C₁₀ alkyl group, may be used. N-butyllithium ispreferred.

[0046] The synthesis of the dihalo metallocene ligand is conducted in anon-interfering medium. Suitable media include hydrocarbons, preferablya C₅ to C₈ alkane, and mixtures of an alkane and ethyl ether. Thesynthesis may be performed at any effective reaction temperature. Apreferred temperature range is from −20° C. to 0° C. The reactionmixture contains the dihalo ligand in the non-interfering medium. Uponcooling, the dihalo ligand separates from the reaction mixture as acrystalline solid which may be removed by filtration under an inertatmosphere, preferably nitrogen. The isolated dihalo ligand may berecrystallized to further reduce impurity content.

[0047] The alkali metal alkyl is used in stoichiometric excess to reducesubstantially all of the group 4(IV) dihalo ligand to the group 4(II)finished catalyst and to reduce any other group 4(IV) compounds whichmay be present in the reaction mixture to group 4(II) compounds or othercompounds of minimal adverse affect on the activity or single sitefunctionality of the finished catalyst. The excess alkali metal alkyl isquenched, for example, with chlorotrimethyl silane. The product isunderstood to comprise a single site catalyst composite essentially freeof group 4(IV) or group 4(III) compounds and other impurities which mayadversely affect single site polymerization activity.

Exemplification of the Invention

[0048] 1. Synthesis of the Cyclopentadienyl Silyl Amine Ligand

[0049] A cyclopentadienyl compound as defined is charged to a vessel.THF is added, preferably at a temperature from about −20° C. to −10° C.,depending upon the cyclopentadienyl compound used.Dimethyldichlorosilane is fed in at a low temperature of about −10° C.to 0° C. The vessel is agitated and the contents warmed to roomtemperature and aluted thereafter. The selected alkylamine, preferably aC₁ to C₁₀ alkyl amine, is fed into the vessel at low temperature, e.g.,about −10° C. After agitation and warming to room temperature, thevessel is heated, and THP and unreacted amine are removed. A slurry mayform. If so, heptane or equivalent hydrocarbon media may be added. Theslurry is filtered. The filtrate contains cyclopentadienyl silyl amineligand (CPSA ligand) of formula:

[0050] in which Z is a cyclopentadienyl group and R is an alkyl groupderived from the alkyl amine reactant.

[0051] 2. Preparation of the Dihalo Ligand

[0052] The dihalo ligand may be synthesized in the manner described inU.S. Pat. No. 6,015,916, Col. 3, I. 60, part (2). In general, thecyclopentadienyl silyl amine may be treated with an unreduced group 4tetrachloride, preferably in the form of a DME or equivalent adduct in ahydrocarbon solvent. The Ti(IV) of the dihalo intermediate is convertedto Ti(II) in the final complex by treatment with an alkali metal alkylas described, preferably butyllithium, and a diene in a non-interfering,preferably hydrocarbon, medium at a preferred temperature of −10° C. to0° C. The alkali metal alkyl is used in stoichiometric excess to reducethe group 4(IV) ligand to the group 4(II) finished catalyst and toreduce any other group 4(IV) compounds which may be present in thereaction mixture. The excess alkali metal alkyl is quenched, preferablywith chlorotrimethylsilane.

Examples Demonstrating Enhanced Polymerization Activity EXAMPLE 1

[0053] All apparatus used in this example were clean, dry andnitrogen-purged. Presence of THEF was precluded.

[0054] 21.2 kg of ethyl ether and 6.5 kg of CpSA ligand (assumed 95%purity) were charged into a first reactor. The pot temperature wasreduced to −20° C.

[0055] 21.2 kg of 15% n-butyllithium in hexane was slowly added with thepot temperature maintained between −20° C. and −10° C. After the feedwas completed, the pot temperature was raised to 20° C. over 1 hour, andthe pot contents were agitated for 4 hours at 20-25° C. A reactionmixture containing a CpSA dilithio salt was produced.

[0056] 34.2 kg of deoxygenated heptane and 2.6 kg of dimethoxyethanewere charged into a second reactor. The pot temperature was adjusted toabout 10-15° C.

[0057] 4.8 kg of titanium tetrachloride were charged to the secondreactor at a pot temperature of between 15° C. and 30° C. Uponcompletion of the feed, the speed of agitation of the second reactorcontents was increased. Agitation continued for about 3 hours at a pottemperature of 20-25° C.

[0058] The pot temperature of each of the first and second reactors wasadjusted to 15-20° C. Thereafter, the contents of the first reactor weretransferred to the second reactor with the pot temperature of the secondreactor maintained at 20-25° C. The second reactor contents were thenagitated for about 12 hours at 25-28° C.

[0059] A reactions mixture containing the dichloride ligand having theformula set forth on page 13 hereof was produced in the second reactor.After solvent stripping, 47.0 kg of deoxygenated heptane was added tothe second reactor. The second reactor pot temperature was adjusted to−15° C. Thereafter, 6 kg of piperylene was charged to the secondreactor. 23.3 kg of EM butyllithium in hexane were fed into the secondreactor. During this feed, the pot temperature was maintained between−15° C. and −10° C. Upon completion of the food, the pot temperature wasadjusted to 20-25° C. over 1 hour. The reaction mixture was agitated forabout three hours at 20-25° C.

[0060] 1.5 kg of trimethylsilicon chloride (TMSCl) was added. The pottemperature was adjusted to 40-45° C. with agitation for 2 hours.Thereafter, the pot temperature was adjusted to 20-25° C., and thereaction mixture was filtered. The cake comprising CGC-7 was rinsed withdeoxygenated heptane.

[0061] Theory yield—9.1 Kg contained

[0062] Actual yield—7.454 Kg contained.

[0063] Activity (determined as described above)—170%.

EXAMPLE 2

[0064] All apparatus used in this example were clean, dry andnitrogen-purged. Presence of THF was precluded.

[0065] 8.5 kg of ethyl ether and 2.6 kg of CpSA ligand (95% purityassumed) were charged into a clean, Isopar-rinsed, nitrogen-purged firstreactor. The pot temperature was −20° C.

[0066] 13.7 kg of deoxygenated Isopar E and 1.0 kg of dimethoxymethanewere charged into a dry, nitrogen-purged second reactor. The pottemperature was adjusted to 10-15° C.

[0067] 1.9 kg of titanium tetrachloride were fed into the second reactorwith slow agitation of the reactor contents and with the pot temperaturemaintained between 15° C. and 30° C. Upon completion of the feed, theagitation was increased, and the contents of the second reactor wereagitated for about 3 hours at 20-25° C.

[0068] The pot temperature of each of the first and second reactors wasadjusted to 15-20° C. The agitated contents of the first reactor weretransferred to the second reactor with the second reactor pottemperature maintained At 20-25° C. The contents of the second reactorwere agitated for about 12 hours at 20-28° C. The reaction mixture inthe second reactor contained the dichloride ligand set forth on page 13hereof. Solvents were stripped from the reaction mixture.

[0069] The pot temperature of the second reactor was adjusted to 15° C.2.0 kg of piperylene were charged to the reactor, 8.5 kg of 15%butyllithium in hexane were slowly fed into the second reactortemperature maintained between −15° C. and −10° C. After the feed wascompleted, the pot temperature was adjusted to 20-25° C. over a 1 hourtime period. The reaction mixture was agitated for 3 hours at 20-25° C.

[0070] 600 g of TMSCl were added, and the reaction mixture was agitatedfor 1 hour. The reaction mixture which contained the desired group 4(II)diene complex was filtered, and the cake was rinsed with deoxygenatedIsopar.

[0071] Theory yield of CGC-7 (contained)—3.65 kg.

[0072] Actual yield of CGC-7 (contained)—2.59 (71% yield)

[0073] Activity (as determined in the manner described above)—140%.

EXAMPLES 3 AND 4

[0074] Synthesis procedures substantially as described in Examples 1 and2 yielded Group 4(II) diene complex products having activities, whendetermined as described above, of 165% and 130%.

We claim:
 1. A compound having the formula

wherein said compound has an olefin polymerization activitysubstantially in excess of loot of standard activity.
 2. The compound ofclaim 1 wherein the olefin polymerization activity of said compound isat least 130% of said standard activity.
 3. The compound of claim 1wherein the olefin polymerization activity of said compound is at least150% of said standard activity.
 4. A method for preparing a compound ofclaim 1 which comprises: (i) providing a first reactor containing thereaction product of a cyclopentadienyl silyl amine and an alkali metalalkyl, (ii) providing a second reactor containing the adduct of formulaMX₄.DME wherein M is a group 4 element, X is a halogen, and DHE isdimethoxyethane, (iii) adjusting the pot temperature of each of saidfirst reactor and said second reactor to be within the ranges of about20° C.-30° C., (iv) thereafter combining the contents of the firstreactor with the contents of the second reactor wherein a reactionmixture is produced in said second reactor, and wherein said reactionmixture produced in said second reactor contains a compound of theformula

(v) distilling solvents from said reaction mixture containing saidcompound in said second reactor, (vi) converting said step (iv) compoundto a compound as set forth in claim 1, and wherein said compound as setforth in claim 1 produced in step (iv) has olefin polymerizationactivity substantially in excess of 100% of the standard activity.
 5. Aligand of a compound of claim 1 wherein said ligand has the formula:

wherein X is a halogen and R is a C₁ to C₁₀ alkyl group.
 6. The ligandof claim 5 wherein X is chlorine and R is t-butyl.